[PATCH 3/3] target: core: Change the way target_xcopy_do_work sets restiction on max io

[Anastasia Kovaleva <a.kovaleva@yadro.com>]

To determine how many blocks sends in one command, the minimum value is
selected from the hw_max_sectors of both devices. In
target_xcopy_do_work, hw_max_sectors are used as blocks, not sectors; it
also ignores the fact that sectors can be of different sizes, for
example 512 and 4096 bytes. Because of this, a number of blocks can be
transmitted that the device will not be able to accept.

Change the selection of max thransmition size into bytes.

Signed-off-by: Anastasia Kovaleva <a.kovaleva@yadro.com>
Reviewed-by: Konstantin Shelekhin <k.shelekhin@yadro.com>
Reviewed-by: Dmitriy Bogdanov <d.bogdanov@yadro.com>
---
 drivers/target/target_core_xcopy.c | 68 ++++++++++++++++--------------
 drivers/target/target_core_xcopy.h |  2 +-
 2 files changed, 37 insertions(+), 33 deletions(-)

diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 6bb20aa9c5bc..c9341a92b567 100644
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -582,11 +582,11 @@ static int target_xcopy_read_source(
 	struct xcopy_op *xop,
 	struct se_device *src_dev,
 	sector_t src_lba,
-	u32 src_sectors)
+	u32 src_bytes)
 {
 	struct xcopy_pt_cmd xpt_cmd;
 	struct se_cmd *se_cmd = &xpt_cmd.se_cmd;
-	u32 length = (src_sectors * src_dev->dev_attrib.block_size);
+	u32 transfer_length = src_bytes / src_dev->dev_attrib.block_size;
 	int rc;
 	unsigned char cdb[16];
 	bool remote_port = (xop->op_origin == XCOL_DEST_RECV_OP);
@@ -597,11 +597,11 @@ static int target_xcopy_read_source(
 	memset(&cdb[0], 0, 16);
 	cdb[0] = READ_16;
 	put_unaligned_be64(src_lba, &cdb[2]);
-	put_unaligned_be32(src_sectors, &cdb[10]);
-	pr_debug("XCOPY: Built READ_16: LBA: %llu Sectors: %u Length: %u\n",
-		(unsigned long long)src_lba, src_sectors, length);
+	put_unaligned_be32(transfer_length, &cdb[10]);
+	pr_debug("XCOPY: Built READ_16: LBA: %llu Blocks: %u Length: %u\n",
+		(unsigned long long)src_lba, transfer_length, src_bytes);
 
-	__target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, length,
+	__target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, src_bytes,
 			  DMA_FROM_DEVICE, 0, &xpt_cmd.sense_buffer[0], 0);
 
 	rc = target_xcopy_setup_pt_cmd(&xpt_cmd, xop, src_dev, &cdb[0],
@@ -627,11 +627,11 @@ static int target_xcopy_write_destination(
 	struct xcopy_op *xop,
 	struct se_device *dst_dev,
 	sector_t dst_lba,
-	u32 dst_sectors)
+	u32 dst_bytes)
 {
 	struct xcopy_pt_cmd xpt_cmd;
 	struct se_cmd *se_cmd = &xpt_cmd.se_cmd;
-	u32 length = (dst_sectors * dst_dev->dev_attrib.block_size);
+	u32 transfer_length = dst_bytes / dst_dev->dev_attrib.block_size;
 	int rc;
 	unsigned char cdb[16];
 	bool remote_port = (xop->op_origin == XCOL_SOURCE_RECV_OP);
@@ -642,11 +642,11 @@ static int target_xcopy_write_destination(
 	memset(&cdb[0], 0, 16);
 	cdb[0] = WRITE_16;
 	put_unaligned_be64(dst_lba, &cdb[2]);
-	put_unaligned_be32(dst_sectors, &cdb[10]);
-	pr_debug("XCOPY: Built WRITE_16: LBA: %llu Sectors: %u Length: %u\n",
-		(unsigned long long)dst_lba, dst_sectors, length);
+	put_unaligned_be32(transfer_length, &cdb[10]);
+	pr_debug("XCOPY: Built WRITE_16: LBA: %llu Blocks: %u Length: %u\n",
+		(unsigned long long)dst_lba, transfer_length, dst_bytes);
 
-	__target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, length,
+	__target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, dst_bytes,
 			  DMA_TO_DEVICE, 0, &xpt_cmd.sense_buffer[0], 0);
 
 	rc = target_xcopy_setup_pt_cmd(&xpt_cmd, xop, dst_dev, &cdb[0],
@@ -670,9 +670,10 @@ static void target_xcopy_do_work(struct work_struct *work)
 	struct se_cmd *ec_cmd = xop->xop_se_cmd;
 	struct se_device *src_dev, *dst_dev;
 	sector_t src_lba, dst_lba, end_lba;
-	unsigned int max_sectors;
+	unsigned long long int max_bytes, max_bytes_src, max_bytes_dst, max_blocks;
 	int rc = 0;
-	unsigned short nolb, max_nolb, copied_nolb = 0;
+	unsigned short nolb;
+	unsigned int copied_bytes = 0;
 	sense_reason_t sense_rc;
 
 	sense_rc = target_parse_xcopy_cmd(xop);
@@ -691,23 +692,26 @@ static void target_xcopy_do_work(struct work_struct *work)
 	nolb = xop->nolb;
 	end_lba = src_lba + nolb;
 	/*
-	 * Break up XCOPY I/O into hw_max_sectors sized I/O based on the
-	 * smallest max_sectors between src_dev + dev_dev, or
+	 * Break up XCOPY I/O into hw_max_sectors * hw_block_size sized
+	 * I/O based on the smallest max_bytes between src_dev + dst_dev
 	 */
-	max_sectors = min(src_dev->dev_attrib.hw_max_sectors,
-			  dst_dev->dev_attrib.hw_max_sectors);
-	max_sectors = min_t(u32, max_sectors, XCOPY_MAX_SECTORS);
+	max_bytes_src = (unsigned long long) src_dev->dev_attrib.hw_max_sectors *
+			src_dev->dev_attrib.hw_block_size;
+	max_bytes_dst = (unsigned long long) dst_dev->dev_attrib.hw_max_sectors *
+			dst_dev->dev_attrib.hw_block_size;
 
-	max_nolb = min_t(u16, max_sectors, ((u16)(~0U)));
+	max_bytes = min_t(u64, max_bytes_src, max_bytes_dst);
+	max_bytes = min_t(u64, max_bytes, XCOPY_MAX_BYTES);
+	max_blocks = max_bytes / src_dev->dev_attrib.block_size;
 
-	pr_debug("target_xcopy_do_work: nolb: %hu, max_nolb: %hu end_lba: %llu\n",
-			nolb, max_nolb, (unsigned long long)end_lba);
+	pr_debug("target_xcopy_do_work: nolb: %hu, max_blocks: %llu end_lba: %llu\n",
+			nolb, max_blocks, (unsigned long long)end_lba);
 	pr_debug("target_xcopy_do_work: Starting src_lba: %llu, dst_lba: %llu\n",
 			(unsigned long long)src_lba, (unsigned long long)dst_lba);
 
-	while (src_lba < end_lba) {
-		unsigned short cur_nolb = min(nolb, max_nolb);
-		u32 cur_bytes = cur_nolb * src_dev->dev_attrib.block_size;
+	while (nolb) {
+		u32 cur_bytes = min_t(u64, max_bytes, nolb * src_dev->dev_attrib.block_size);
+		unsigned short cur_nolb = cur_bytes / src_dev->dev_attrib.block_size;
 
 		if (cur_bytes != xop->xop_data_bytes) {
 			/*
@@ -727,11 +731,11 @@ static void target_xcopy_do_work(struct work_struct *work)
 		pr_debug("target_xcopy_do_work: Calling read src_dev: %p src_lba: %llu,"
 			" cur_nolb: %hu\n", src_dev, (unsigned long long)src_lba, cur_nolb);
 
-		rc = target_xcopy_read_source(ec_cmd, xop, src_dev, src_lba, cur_nolb);
+		rc = target_xcopy_read_source(ec_cmd, xop, src_dev, src_lba, cur_bytes);
 		if (rc < 0)
 			goto out;
 
-		src_lba += cur_nolb;
+		src_lba += cur_bytes / src_dev->dev_attrib.block_size;
 		pr_debug("target_xcopy_do_work: Incremented READ src_lba to %llu\n",
 				(unsigned long long)src_lba);
 
@@ -739,16 +743,16 @@ static void target_xcopy_do_work(struct work_struct *work)
 			" cur_nolb: %hu\n", dst_dev, (unsigned long long)dst_lba, cur_nolb);
 
 		rc = target_xcopy_write_destination(ec_cmd, xop, dst_dev,
-						dst_lba, cur_nolb);
+						dst_lba, cur_bytes);
 		if (rc < 0)
 			goto out;
 
-		dst_lba += cur_nolb;
+		dst_lba += cur_bytes / dst_dev->dev_attrib.block_size;
 		pr_debug("target_xcopy_do_work: Incremented WRITE dst_lba to %llu\n",
 				(unsigned long long)dst_lba);
 
-		copied_nolb += cur_nolb;
-		nolb -= cur_nolb;
+		copied_bytes += cur_bytes;
+		nolb -= cur_bytes / src_dev->dev_attrib.block_size;
 	}
 
 	xcopy_pt_undepend_remotedev(xop);
@@ -758,7 +762,7 @@ static void target_xcopy_do_work(struct work_struct *work)
 	pr_debug("target_xcopy_do_work: Final src_lba: %llu, dst_lba: %llu\n",
 		(unsigned long long)src_lba, (unsigned long long)dst_lba);
 	pr_debug("target_xcopy_do_work: Blocks copied: %hu, Bytes Copied: %u\n",
-		copied_nolb, copied_nolb * dst_dev->dev_attrib.block_size);
+		copied_bytes / dst_dev->dev_attrib.block_size, copied_bytes);
 
 	pr_debug("target_xcopy_do_work: Setting X-COPY GOOD status -> sending response\n");
 	target_complete_cmd(ec_cmd, SAM_STAT_GOOD);
diff --git a/drivers/target/target_core_xcopy.h b/drivers/target/target_core_xcopy.h
index e5f20005179a..51a8e4d85d3e 100644
--- a/drivers/target/target_core_xcopy.h
+++ b/drivers/target/target_core_xcopy.h
@@ -5,7 +5,7 @@
 #define XCOPY_TARGET_DESC_LEN		32
 #define XCOPY_SEGMENT_DESC_LEN		28
 #define XCOPY_NAA_IEEE_REGEX_LEN	16
-#define XCOPY_MAX_SECTORS		4096
+#define XCOPY_MAX_BYTES 		16777216 /* 16 MB */
 
 /*
  * SPC4r37 6.4.6.1
-- 
2.30.2